Frequency dividers play an important role in phase-locked loops (PLLs) and are also a key circuit in wireless communication systems. There are generally three types of frequency dividers, including current mode logic (CML) frequency dividers, injection-locked frequency dividers, and regenerative frequency dividers.
In general, the CML frequency divider has good sensitivity and bandwidth. However, limited by its component's cut-off frequency (ft), the CML frequency divider generally has a low operating frequency. Although the operating frequency of the regenerative frequency divider is higher than that of the CML frequency divider, the regenerative frequency divider has high direct current power consumption. The injection-locked frequency divider has low power consumption as well as high operating frequency, but the locking range thereof is usually narrow. Therefore, the injection frequency dividers have limited use in current wireless communication systems which call for high data amount transmission, low voltage and low power consumption.